Recent Trends in Anti-crease finishing of cotton

1. Seminar Report On
“Recent Trends in Anti-crease finishing of cotton”
Submitted in partial fulfilment of the Requirements for the award of the degree
of BACHELOR OF TECHNOLOGY
in
TEXTILE CHEMISTRY
Submitted By
Vijay Prakash (1704460060)
Textile Chemistry
Under the Guidance of
DR. A.K. PATRA Sir
Professor & Head (Textile Chemistry) UPTTI (formerly GCTI)
Souterganj, Kanpur - 208001
(State-UP) INDIA

2. Submitted to:
DEPARTMENT OF TEXTILE CHEMISTRY
Uttar Pradesh Textile Technology Institute, Kanpur
24 July 2021

3. CHAPTER PAGE
ACKNOWLEDGMENTS………………………………………………………………………………...……....I
ABSTRACT …………………………………………………………………………………….II
INTRODUCTION ……………………………………………………………………………………………..III THE
TERM CREASE AND WRINKLES …………………………………………………………………IV WHY
CREASE FORM ON COTTON (CELLULOSIC FABRIC)? ……………………………………….V
EXPERIMENTAL ……………………………………………………………………………………VI
MATERIALS AND METHODS ……………………………………………………………………………VII
SYNTHESIS AND CHARACTERIZATION OF ACRYLATE COPOLYME ………………………………VIII
CHEMICAL TREATMENTS ………………………………………………………………………………… IX
EFFECT OF COPOLYMER TG AND MOLECULAR WEIGH ON TENSILE STRENGTH RETENTION……
RESULTS AND DISCUSSION …………………………………………………………………………… XI
EFFECT OF COPOLYMER -TG AND MOLECULAR WEIGHT ON DCRA ………………………… XII
FORMALDEHYDE FREE CREASE-RESISTANT FINISHING OF COTTON FABRIC USING CITRIC
ACID. ……………………………………………………………………………………………………… XIII
TABLE OF CONTENTS

4. MATERIALS AND CHEMICAL……………………………….…………………..…………………………………….
XIV
PREPARATION OF SILK FIBROIN ……….………………………………………….……………………………….
XV
EFFECT OF CA/FIBROIN CONCENTRATION ON CREASE RECOVERY OF THE TREATED
FABRIC……XVI
CONCLUSION…………………………………………………………………………………………………….………………
XVIII
REFRENSES
……………………………………………………………………………………………………………………….XIX

5. ACKNOWLEDGEMENT
Present inspiration and motivation have always played a key role in the success of any venture.
I offer my profound gratitude to the management of UPTTI, Kanpur. For giving me the opportunity to
do prepare the project report. I express my sincere thanks to Dr. G. Nalankilli, Director of Uttar
Pradesh Textile Technology Institute, Kanpur.
I pay my deep sense of gratitude to Dr. ARUN KUMAR PATRA Sir, HOD of Textile Chemistry
department and Academic HOD, UPTTI Kanpur to encourage me to the highest peak and to provide me
the opportunity to prepare the project.
I feel to acknowledge my indebtedness and deep sense of gratitude to Dr. Patra sir whose valuable
guidance and kind supervision given to me throughout the course which shaped the present work as its
show. I am immensely obliged to my friends for their elevating inspiration, encouraging guidance and
kind supervision in the completion of my project.
Last, but not least, My Parents are also an important inspiration for me. So, with due regards. I express
my gratitude to them.
VIJAY PRAKASH
1704460060
Textile Chemistry
Uttar Pradesh Textile Technology Institute Kanpur,
Uttar Pradesh

6. A simultaneous treatment of cotton fabric with 4,5-dihydroxy-1,3
dimethylethyleneurea and an acrylate copolymer was studied. When acrylate
copolymers with low glass transition temperatures (below – 22 degree C) and high
molecular weight (above 105
) were used with the crosslinking agent, the treated
fabrics had an excellent level of crease resistance, tensile strength, and flex-
abrasion resistance. Good durability to repeated launderings, resistance to
hydrolysis, wash-wear rating, shrink resistance, and color fastness were also
obtained on the resin-finished cotton fabrics. A paddry- cure process was applied
to various kinds of cotton fabrics using a production machine. No formaldehyde
was detected during processing or from the resin-treated fabrics thus produced.
ABSTRACT

7. Wrinkling effect in cellulose fiber–made fabrics has a major setback for their use as
apparels necessitating the use of crease resistance finish. For a while,
formaldehyde-based-finished dimethyl dihydroxy ethylene urea has been used as crease
resistance finish. DMDHEU finished fabric will releases formaldehyde during its
application, that affects both user’s health and the environment. This research optimized
citric acid (CA) and silk fibroin solution as a crease resistance finishing agent. Citric acid
was identified as a non-formaldehyde-based cross- linking agent but causes yellowing in
cotton fabrics. To steer clear of this, silk fibroin solution was added with citric acid to
increase the crease resistant in avoiding yellowing of the fabric caused by citric acid. The
optimum combination of the processing parameters obtained was 6% silk fibroin solution, 30
g/L of citric acid, and 6% sodium dihydrogen phosphate, at a finishing bath at pH of 5.5
with curing temperature of 150°C. These optimized finishing parameters achieved a dry
crease recovery angle of 252° while obtaining an 84% tensile strength retention, 96%
tearing strength retention, and 75 WI (93%) whiteness index.

8. Introduction:
Cotton is one of the most favoured textile materials because of its superior wearing
comfort and excellent wearability. Unfortunately, cotton fabric wrinkles easily
during home laundering and causes considerable inconvenience for users. The poor
resiliency of cotton is caused by the structure of biopolymer-cellulose in fibers, as
it has hydrogen bonds as the major intermolecular interactions but is lack of
intermolecular chemical cross-linkages. Crosslinking of cellulose with
formaldehyde-based compounds, mainly dimethylol dihydroxy ethylene urea
(DMDHEU) was introduced to overcome winkles. DMDHEU has been used in
cotton finishing for prominent wrinkle resistance property since 1950s. However,
when treated cotton fabric is subjected to multiple laundering cycles, ether linkages
of DMDHEU gradually hydrolyse to become N-methylol groups. Hence, free
formaldehyde releases continuously during the entire life of the treated garment. In
1987, the U.S. Environmental Protection Agency classified formaldehydes “a
probable human carcinogen” (Environmental Protection).

9. Many researchers have been dedicated in finding and developing formaldehyde- free easy-
care agents or finishes for cotton fabric. Polycarboxylic acids (PCA) are non-formaldehyde
reactants that have the possibility of replacing the conventional finishing agents. Among the
various effective agents, carboxylic acids, 1,2,3,4- butanetetracarboxylic acid (BTCA) is the
most effective cross-linking agent for the cotton fabrics (Sunder and Nalankilli 2012; Yang
and Hu 2006). Even though BTCA in the presence of sodium hypophosphite provides the
same level of DP performance and better mechanical properties as found in DMDHEU-
treated cotton fabrics, its high cost is an obstacle for mills to use it as replacement for
conventional DP reactants. Citric acid (CA) is another candidate that could replace DMDHEU.
The advantages of citric acid over others of the Polycarboxylic acids are its low cost, lack of
toxicity, and readily available. However, finishing based on citric acid alone causes yellowing
in cotton fabrics due to formation of unsaturated acid.
In the present study, an attempt has been made to find the optimum processing parameters
used for citric acid and fibroin solution as a DP finish treatment on cotton fabric to
improve the appearance properties of fabrics treated with citric acid and to minimize the
associated yellowing problem.

10. The term Crease and Wrinkles:
Creases are a fold in a fabric introduced unintentionally. The definition of a
wrinkle is less clear, however. Some define wrinkles as three-dimensional creases,
whereas others define them as short and irregular creases. They form when fabrics
undergo double curvature, which occurs when a flat material is bent in both of its
planes. Sufficient force must be applied that the change is permanent to some
degree. Some people use the terms ‘wrinkle’ and ‘crease’interchangeably.
Wrinkles and creases are distinct to pleats, because pleats are introduced
intentionally and over regular intervals. They are usually sharp folds, often running
lengthways to give a decorative effect.
Crease marks are marks left in a fabric once the crease has been removed and are
usually caused by mechanical damage.
Crease resistance is the ability of a material to resist, or recover from, creasing.
Crease recovery is a specific measurement of crease resistance that determines the
crease recovery angle. It is therefore a quantitative method of analysis.

11. Why crease form on cotton (cellulosic fabric)?
Cotton (like most plants) is made of a substance called cellulose, which contains hydrogen - an
essential ingredient in water. When this material is woven into a piece of apparel - like a shirt -
the hydrogen particles are attracted to each other and form a bond. This gives the shirt shape and
helps it to maintain its form when it's worn, sat upon or folded - unless you get wet.
If you sweat, spend time in a humid area, spill a liquid on yourself or wash your shirt, it
wrinkles. It does this because the hydrogen links in the cotton react to water, causing the fabric
to bend out of shape and form wrinkles in the cloth.
So, now that you know how wrinkles are happen, how do you prevent them? Well, obviously, it's
difficult to prevent ourselves from sweating when it's hot and sometimes we can't avoid humid
environments - so the next best thing to do is treat the fibers with something that's waterproof to
prevent the hydrogen bonds from breaking.
Today this is accomplished with non-toxic, chemical treatments, leaving your cotton clothing
looking crisp and sharp all day long. This type of apparel is especially appealing to travellers,
golfers - and those of us who dislike irons.

12. EXPERIMENTAL
MATERIALS AND METHODS:
Fabrics:
The fabrics were a 100% cotton poplin, a 100% cotton sateen of 129 g/m2, and a
polyester/cotton (65/35) blend broad weave of 143 g/m2. The poplin was used
unless otherwise specified. The fabrics were singed, desized, scoured, and
mercerized on a production machine. Various kinds of fabrics were also used for
testing in the large-scale production process.
Synthesis and Characterization of Acrylate Copolymers:
Acrylate copolymers were prepared by emulsion polymerization. The various Tg of
the copolymers, determined by differential scanning calorimetry, were - 54°C, - 22°C,
and 26°C, respectively.
Number average molecular weight (M) of the copolymers was determined by gel
permeation chromatography. The calibration curve was constructed from the peaks in
the elution pattern of polymethyl methacrylate of known molecular weights. Most
copolymers applied to cotton fabrics were M = 105. One copolymer of lower molecular
weight, M = 1 0~, and Tg of - 54°C was also prepared and applied.

13. Chemical Treatments:
The fabrics were immersed in an emulsion solution containing acrylate copolymer, DHDMEU,
and zinc fluoroborate. Optimum concentration of catalyst was determined by a
screening study. A copolymer formulation containing 4,5- dihydroxyethyleneurea
(DHEU) and magnesium chloride hexahydrate with 2- amino-2-methyl-1-propanol was
also used for the experiment on the effect of pH on dry crease recovery angles (DCRA).
For comparison, a conventional resin- treatment was performed using 4,5-dihydroxy-
1,3-dimethylol ethylene urea (DMDHEU) of low formaldehyde type crosslinking agent.
Magnesium chloride hexahydrate was used as the catalyst of DMDHEU. The fabrics were
padded to 70% wet pick-up, dried for 3.5 min at I 20°C, and then cured for 3.5 min at 150°C.

14. Chemistry
The crosslinking agents that result in the permanent-press finish are often
derivatives of urea. Popular crosslinkers include DMDHEU (dimethylol
dihydroxyethyleneurea) and DMEU (dimethylol ethylene urea).

15. Test Methods
Physical tests of the fabrics were carried out at 65% RH and 20°C by standard test
procedures. DCRA and wet crease recovery angles (WCRA) were determined using
the same procedure as described in a previous report. Tear strength was measured by
ASTM D 1424-63 (Elmendorf) method. Wash-wear rating was determined by
AATCC 88B-1975 (IIIC). Shrinkage resistance was determined by AATCC 88B-1975
(IIIC) with drying at 130°C for 30 s in a flat-bed press under pressure of 60
pounds/inch’. Flex-abrasion resistance tests were performed by JIS L 1004-1978 A
Stiffness of the fabrics was measured by Handle- O-Meter and presented as the sum of
values in warp and filling directions on both sides of fabrics.
Color Fastness
The tests of dry and wet crocking were performed by the AATCC 8-1969
procedure.
Results and Discussion

16. EFFECT OF COPOLYMER Tg AND MOLECULAR WEIGH ON TENSILE
STRENGTH RETENTION
Relationships between the retention index of the tensile strength and DCRA values
after resin treatment are shown in Figure 3. As expected from the crease recovery
properties, the fabrics treated with the copolymer systems exhibit higher values for
the retention index of tensile strength than the fabrics treated without copolymer.
Straight lines with similar slopes are observed for the different systems employed.
At a given DCRA value, the tensile strength of the treated fabrics increases as the
Tg of the copolymer decreases. However, the strength retention is lowered as the
molecular weight of the copolymer decreases to about 104. Therefore, the film-
forming property of polymer is important in enhancing tensile strength
retention.

17. FIGURE 4. Scanning electron micrograph of the
cotton fibers on the surface of the fabric treated with
the system including 10% DHDMEU and 1.6%
copolymer having T. of -54°C and molecular weight
of n,, 105.

18. Disadvantage:
 Yellowness
 Harm to human helth
 Weight loose
 Dryness
 Reduction in tear strength
 Reduction in durability

19. Results and Discussion:
EFFECT OF COPOLYMER -Tg AND MOLECULAR WEIGHT ON DCRA
The effects of Tg and molecular weight of the copolymers on DCRA at various
concentrations of DHDMEU. The DCRA values of the resin-treated fabrics are
remarkably increased by simultaneous treatment with copolymers and DHDMEU.
The Tg of the copolymer is an important factor controlling the value of DCRA.
The fabrics treated with the copolymer system with the lowest Tg examined show
particularly high DCRA values. When Tg of the copolymers is decreased, DCRA
values are greatly increased, and this tendency is more propounced with an
increase in the DHDMEU concentration. When the DCRA values obtained from
the simultaneous treatment are compared to those from treatment without the
copolymer, it is clear that the marked improvement of fabric property is
attributable to the concerted action of the copolymer and the crosslinking agent.

22. Formaldehyde free crease-resistant finishing of cotton fabric using
citric acid.
Materials and methods:
Materials and chemicals
Full bleached 100% plain weave cotton fabric (100%), having the following
structural characteristics, was used: 20s Ne count yarn end per inch; 54 Picks per
inch; and fabric mass per unit area with 150 g/m2 fabric was sourced from Bahir
Dar Textile Share Factory, Bahir Dar, Ethiopia. Bombyx mori silk cocoon was
obtained in raw form Wereta Agriculture College, Bahir Dar, Ethiopia. Fibroin
solution was used as a DP finish. Ethanol (absolute GR for analysis) was obtained
from M/s Merck (Darmstadt, Germany). CA, calcium chloride, and hydrochloric
acid are of laboratory grade. Deionized water was used in all experiments.

23. Methods:
To optimize the process parameters, fabric samples (40 cm × 125 cm) were
impregnated with solution containing different concentrations of CA (10, 20, 30, and
40 g/L), fibroin solution (2%, 4%, 6%, and 8%), and sodium dihydrogen
phosphate (NaH2PO4; 5%, 6%, 7%, and 8%) on a three-bowel padding mangle
using 80% wet pickup (2 dip 2 dip). The padded fabric samples after padding were
dried at 100°C for 5 min and then the curing process was carried out at 140°C,
150°C, 160°C, and 170°C for 2 min in each process in a laboratory curing unit
(Ernst Benz, Model KTF/M).
The cured fabric sample was treated with soap solution (sodium lauryl sulfate 2
g/L) for 5 min in a laboratory jigger and finally rinsed for 10 min at room
temperature and then dried under ambient conditions.
The effects of concentration of CA, fibroin solution, catalyst, and curing
temperature on the fabric properties were investigated separately. For the optimum
conditioning of ease care finishing crease recovery angle, tensile strength, tear
strength and whiteness has been tested.

24. Preparation of silk fibroin solution
Raw silk fibers were degummed thrice with 0.5% (w/w) NaHCO3 solution at
boiling temperature for 60 min and then washed with distilled water. Degummed silk
was dissolved in a ternary solvent system of calcium chloride, ethyl alcohol, and
water (1:2:8 in molar ratio) at 80°C for 6 h. After dialysis with Himedia tubular
dialysis membrane-50 in distilled water for 3 days, pure silk fibroin solution
was filtered. The aqueous silk fibroin solution was hydrolyzed in hydrochloric
acid at 70°C for 150 min and then neutralized with sodium hydroxide.
Application methods of the finishing
The fabric was padded with a bath containing cross-linking agent (CA), fibroin
solution, acid liberating catalyst, sequestering agents, and wetting agent. Fabric was
dried at 100°C and cured at 140°C, 150°C, 160°C, and 170°C for 2 min followed
by washing to remove free formaldehyde and residual catalyst.

25. Measurement of crease recovery
The crease recovery of the fabrics was tested using the Shirley crease recovery
tester and the value reported in this instrument was CRA according to AATCC TM
66-2017 method.
Measurement of tensile strength
Instron machine was used to analyse the tensile strength of the samples, which was
measured by the ravelled strip (20 cm × 5 cm) method. The tensile strength of
fabric was tested as per ASTM D-5035 method.
Measurement of tearing strength
The tearing strength of the fabric samples was determined by the Elmendorf
tearing tester in accordance with ASTM Test Method D 1424-96. A template was
used to cut fabric strips of 100 ± 2 mm length and 63 ± 0.15 mm width. The tearing
strength was then calculated by the following formula:
Tearing strength (g) = Scale reading × 64.
Warp-way and weft-way strips were tested for each sample, and 10 readings were
taken in each sample.

26. Measurement of abrasion
The abrasion of the fabrics was measured by the Martindale abrasion tester and the
weight loss of untreated and finished fabric as per ASTM D-4966 method was
measured. The grades of abrasion were obtained by comparison with the standard
specimens.
Whiteness index (WI) property
Whiteness of the bleached fabrics was determined with reflectance value using i5
Macbeth visible spectrophotometer. Whiteness values were measured at four
different places in the samples and their average was used for the analysis of results.
The WI of fabrics was analysed as per ASTM DE 313-67 standard.
Results and discussion
Effect of CA/fibroin concentration on crease recovery of the treated fabric
The concentration of cross-linking agent has significant effect on the dry crease
recovery angle (DCRA) of crease resistance finishing of treated fabric than that of
untreated fabric (bleached fabric).

27. When the concentration of CA varies as 10, 20, 30, and 40 g/L, the percentage in
DCRA of the treated fabric also increases. As shown in Figure 1(a), the percent
increase was recorded as 58.6%, 65.5%, 73.8%, and 84.8% for the CA
concentration of 10, 20, 30, and 40 g/L, respectively. Figure 1(b) shows the
influence of CA with fibroin solution and without fibroin solution effect on CRA.
With the same concentration of CA, the fibroin solution-treated fabric has more
DCRAthan that of untreated fabric.
The results show that the CA-treated fabric showed more crease resistance angle
increase as the concentration of the cross-linking agent increased. Figure 1(a)
shows that as the concentration of CA increased, the percent in DCRA also
increased significantly.
Effect of catalyst concentration on crease recovery of the treated fabric
To investigate the effect of catalyst concentration on crease recovery of the treated
fabric, the concentration of catalyst varied from 5%, 6%, 7%, and 8%, keeping the
other variables constant.

29. Figure 1. (a) % DCRAincreases as a function of citric acid concentration. (b)
Effect of CA concentration on crease recovery of the treated fabric.

30. Figure 2. DCRA increase as a function of catalyst concentration.
As shown in Figure 2, the DCRA of treated fabric increased as concentration of the
catalyst increased. However, the CRA of the fabric increased up to 6% as
concentration of catalyst increases. After this concentration, the increment of CRA
was not significant.
The percent increase in DCRA of the treated fabric as compared to untreated
bleach fabric was 58%, 74%, 79%, and 79% for the catalyst concentrations of 5%,
6%, 7%, and 8%, respectively.
Conclusion:
Treatment with PCA is a viable and effective method to impart DP properties to
cotton fabrics. The effect of the finishing variables, CA, fibroin solution and
catalyst amounts, and curing temperature were investigated. The CA/fibroin
treatments to the cotton fabric significantly improve its CRA, tensile strength,
tearing strength, and abrasion resistance compared with DMDHEU-treated cotton
fabric. The results showed that CA/fibroin is a very effective cross-linking agent to
the DP finishing of cotton fabrics. Cotton fabrics treated with both CA and fibroin
solution show higher DCRA values than samples treated with CA alone, at the
same curing temperature.

31. Figure 12. Results of tensile strength retention of cotton fabric treated with 30 g/L,
6% fibroin, 6% catalyst and cured at 150°C for 2 min.

32. It was also found that the addition of fibroin and catalyst to CA in the right proportions
leads to the almost complete retention of the mechanical properties originally present in
untreated cotton, which severely reduced with the traditional treatment. The use of fibroin as
additive with CA for the crease-resistant finishing of cotton fabrics increased the crease
resistance of cotton and avoided fabric yellowing caused by CA as a finishing agent for
cotton fabric.
The optimized finishing parameters were given up to 252°C of DCRA and were obtained
with 84%, 96%, 75 WI (93%) tensile strength retention, tearing strength retention, and
reserved WI, respectively. The optimum combination of the processing parameters to
obtain this result was 6% fibroin, 30 g/L of CA, 6% sodium dihydrogen phosphate, at a
pH 5.5 finishing bath and a curing temperature of 150°C.

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